Domestic animals such as cats are susceptible to various diseases, ailments and conditions, which are not only arduous and painful for the animal itself but also a source of concern and stress for animal owners. While animal owners nurture, watch over and bestow affection on their pets, they must balance this attention with other responsibilities. Convenience is thus an important factor when taking care of a domestic animal. While owners may be devoted and considerate to their pets, they may lack the sophistication to diagnose animal diseases, ailments and conditions. Convenient, simple and effective means to inform pet owners of the presence of diseases, such as urinary infections, are desired so that appropriate steps can be taken to reverse, mitigate or avoid serious illness in the animal.
For example, feline urinary tract disease can be a serious condition for cats. In feline urinary tract disease, crystals of magnesium ammonium phosphate can precipitate in the cat's urinary tract and cause obstruction. If untreated, the obstruction can lead to intense pain and can often be fatal within days. In some cases, upon observing feline urinary tract disease symptoms—such as bloody urine and urination discomfort and straining—cat owners often consult their veterinarian who may be able to provide treatments, which may be expensive. However, many cats with feline urinary tract disease do not show any obvious symptoms, which is why this disease has been referred to as a “silent killer”.
Early detection of feline urinary tract disease is therefore of paramount importance in facilitating treatment, lessening the likelihood of severe complications or aggravations, and reducing the cost of treatment.
Some methods of early detection are known. Early detection may be possible by occult blood testing, allowing animal owners to treat the problem of urinary tract disease by changing the animals' diets. However, some known occult blood testing techniques present various disadvantages concerning the complexity and inconvenience of the tests. For instance, animals will often resist urine sample gathering.
It is known to use diagnostic agents, incorporated into test strips, beads or particles, for detection purposes. Usually, such test strips consist of an absorbent carrier made from fibrous or non-woven material, in the simplest case filter paper, which is coated or impregnated with the detection reagents. Components of the detection reagent may be a chromogen as an indicator, an oxidizing agent such as a hydroperoxide as an oxidizer of the indicator. The oxidizing agent is sometimes also called a sensitizer or an accelerator. Standard additional components are, apart from a surface-active agent (wetting agent), thickening agents which prevent the bleeding of the wetted test field, pigments, complex-forming agents and/or other stabilizers for the chromogen and/or the hydroperoxide.
Similarly, various analytical methods are presently available for detecting the presence of “peroxidatively active substances” in samples such as urine, fecal suspensions, and gastrointestinal contents. According to U.S. Pat. No. 4,460,684, hemoglobin and its derivatives are typical of such peroxidatively active substances because they behave in a manner similar to the enzyme peroxidase. Such substances are also referred to as pseudoperoxidases. Peroxidatively active substances are enzyme-like in that they catalyze the redox reaction between peroxides and benzidine, o-tolidine, 3,3′,5,5′-tetramethylbenzidine, 2,7-diaminofluorene or similar benzidine-type indicator substances, thereby producing a detectable response such as a color change. Most methods for determining the presence of occult blood in test samples rely on this pseudoperoxidatic activity. A benzidine-type indicator responds in the presence of hydroperoxide and peroxidase by changing its light absorptive capability.
Providing a reliable occult blood detection system in animal litter itself also has many problems and challenges. For example, the test indicator material should be stable when exposed to a wide variety of ambient conditions, be they dry or humid, and over a wide range of temperatures. Such stability is quite often difficult to achieve.
A further problem with many known test indicators is that pet owners are insufficiently observant or sophisticated to appreciate the positive indication, such as a color change, before the indicator decays. Many known indicators do not stay at the changed color for a sufficient period of time to allow pet owners to reliably recognize the indicated health issue.
An additional problem with various detection reagents mixed with animal litter is that the test reagents give off sufficient scent such that cats, which have an extraordinary sense of smell, recognize the odor change in their litter and thus tend to shy away from the litter. As will be appreciated, this not only defeats the purpose of a convenient detector but can also cause unwanted excretory mishaps. Thus, test reagents with significant, offensive or upsetting odors—both to the user and the cat—have many disadvantages.
A further problem with known detection reagents is poor shelf life stability, particularly if combined with an animal litter for storage as a single mixture. Poor stability leads to disadvantages in the ability to store, transport, display, purchase and use the detection-litter combination.
Detection materials that are merely coated over the surface of a carrier material also have various disadvantages that may relate to poor shelf-life stability, low in-use stability and lifetime, and insufficient color change visibility.
Known materials and methods for detection of animal excretion tract disease have involved one or more of the above deficiencies.
Some detection methods are disclosed in WO 2010133001 (Jollez et al.) which describes a chromogenic composite material for use with animal litter. The composite material can include an absorptive polymer material; clay; a chromogenic indicator; and an oxidizing agent that is available and responsive to peroxidase or pseudoperoxidase activity in the feline urine to activate the chromogenic indicator. The chromogenic indicator may be 3,3′,5,5′-tetramethylbenzidine, also referred to as TMB.
As for TMB, it is an electron donor that can reduce hydrogen peroxide in presence of peroxidase enzyme. In ambient conditions, TMB may be present as a white crystal powder that is only slightly soluble in aqueous solutions. Organic solvents may therefore have been preferred to solubilize TMB for applications.
Despite the developments in detection methods for animal excretion tract disease, there is still a need for an improved technology. In order to improve solubility of TMB in water, water soluble inclusion complexes have been employed in certain fields.